Touching of a capacitive sensor by a human hand or finger, or approaching a capacitive proximity sensor changes certain parameters thereof, in particular the capacitance value of a capacitor that is built into the touch sensor used, for example, in human to machine interface devices, e.g., keypad or keyboard. Microcontrollers now include peripherals that enhance the detection and evaluation of such capacitive touch sensors. One such application utilizes capacitive voltage division (CVD) to evaluate whether a capacitive touch element has been touched or not. The CVD conversion process requires that the sensor and ADC sample-and-hold capacitors be charged/discharged/connected for precise time periods to achieve full resolution with minimum noise.
Typical systems use software to perform the CVD conversion. However, this requires high processor overhead and usage of significant amounts of program memory, and achieves only coarse timing resolution. Hence there exists a need for an improved microcontroller capable of interfacing with capacitive touch sensors.